Cable routing in V slot

[Lol999]

Sorry if this is the wrong place, mods please move as appropriate.

I am assembling a small cnc laser and I want to change the cable routing. I'm using cable chains/drag chains but it would be useful to be able to route some cables actually in the groove of the 2040 extrusion.
Obviously it would need something to hold it in place that would allow gantry carriage etc to traverse it without getting fouled but I just can't find anything.

I seem to remember seeing once a sort of tubing inserted into the slot to carry cables but how it worked or where it can be accessed I have no idea.

Can anyone help me with this one please?

[Soyb]

Ooznest has slot cover https://ooznest.co.uk/product/slot-cover/ or thingiverse has 3d printed clips and holders

[Lol999]

cheers mate!